debian: fix up package descriptions
debian: fix up package descriptions

Drawing inspiration from xcffib's package descriptions, we add a specific
one for python2 and python3 as debian suggests. We also add a custom
qtile binary-specific package description as well.

This silences:
https://lintian.debian.org/tags/description-synopsis-might-not-be-phrased-properly.html
https://lintian.debian.org/tags/duplicate-long-description.html

soulchainer/qtile,flacjacket/qtile,cortesi/qtile,jdowner/qtile,qtile/qtile,frostidaho/qtile,kynikos/qtile,kynikos/qtile,flacjacket/qtile,himaaaatti/qtile,de-vri-es/qtile,tych0/qtile,de-vri-es/qtile,ramnes/qtile,ramnes/qtile,zordsdavini/qtile,rxcomm/qtile,qtile/qtile,frostidaho/qtile,soulchainer/qtile,cortesi/qtile,rxcomm/qtile,jdowner/qtile,zordsdavini/qtile,dequis/qtile,tych0/qtile,dequis/qtile,himaaaatti/qtile